Reserve valve mechanism permitting refilling of scuba tank regardlessof valve setting

ABSTRACT

A reserve mechanism for use with a self-contained breathing apparatus includes a valve which permits the breathing gas supply tank to be refilled regardless of the valve setting. The valve includes two cooperating members, an annular valve seat member and a piston member, which are spring biased toward a flow impeding position. Each member is movable in a direction opposite the other, so that the valve opens when the gas pressure in either direction exceeds the spring bias force. This permits gas from a compressor or other source to flow in the reverse direction through the valve and refill the tank even though the valve is not set to the manually opened, &#39;&#39;&#39;&#39;reserve&#39;&#39;&#39;&#39; position.

United States Patent 1 Leemann June 28, 1974 RESERVEVALVE MECHANISMPERMITTING REFILLING OF SCUBA TANK REGARDLESS OF VALVE SETTING Inventor:Karl Leemann, Wehntalersh 142 8057, Zurich, Switzerland Filed: Jan. 29,1973 Appl. No.: 327,719

US. Cl. l37/493.4, 137/495 Int. Cl. F16k 45/00, Fl6k 17/00 Field ofSearch 137/495, 508, 493, 493.4, 137/512.5, 523, 530, 543.15, 493.6,493.9, 494, 63 R; 128/l45.7, 202, 145.6

References Cited UNITED STATES PATENTS 3,722,535 3/1973 Ruupp 137/493.4

Primary Examiner-Henry T. Klinksiek Assistant Examiner-Robert J. MillerAttorney, Agent, or Firm Flam & Flam 57] ABSTRACT A reserve mechanismfor use with a self-contained breathing apparatus includes a valve whichpermits the breathing gas supply tank to be refilled regardless of thevalve setting. The valve includes two cooperating members, an annularvalve seat member and a piston member, which are spring biased toward aflow impeding position. Each member is movable in a direction oppositethe other, so that the valve opens when the gas pressure in eitherdirection exceeds the spring bias force. This permits gas from acompressor or other source to flow in the reverse direction through thevalve and refill the tank even though the valve is not set to themanually opened, reserve" position.

8 Claims, 5 Drawing Figures PATENTEDJUN28 m4 SHEET 1 [IF 2 Q mmREFILLING OF SCUBA TANK REGARDLESS OF VALVE SETTING BACKGROUND OF THEINVENTION 1. Field of the Invention The present invention relates to ascuba reserve mechanism which permits refilling of the scuba tankregardless of the setting of the reservevalve.

2. Description of the Prior Art To allow safe return to the surface, theuser of a selfcontained underwater breathing apparatus (scuba) mustbegin his ascent when there is yet a supply of breathable gases in histank adequate for the ascent. For this purpose, known reserve valves areused which include a springbiased closure which actually shuts off theflow of breathable gas when the scuba tank pressure drops to avaluecorresponding to the spring force. Thereupon the diver operates a manualoverride to retract the closure, and the flow of breathable gas isreestablished. However the diver now knows that the tank supply is notexhausted, and he begins his ascent.

A'problem arises when the tank is refilledjlf the reserve valve is leftin the reserve position with the closure retracted, the tank can berefilled normally through the open valve. But if the reserve valveshould be set with the closure biased to aflow impeding position, thetank cannot be refilled. Air from the compressor, flowing in a directionopposite that associated with scuba breathing, will not open theclosure, and may force it more tightly shut. This situation may not benoticed until the next dive with that tank, when the diverquickly'learns that his tank is substantially empty.

This problem is particularly acute should the unfilled tank be usedwith-a properly filled tank in a tandem arrangement with a singlereserve valve. When the valve is switched to reserve, the air remainingin the previously filled tank is partly distributed to the unfilledtank, causing the pressure of the available air suddenly to decrease.

The principal object of the present invention is to provide a reservevalve mechanism which will permit the associated scuba tank to berefilled regardless of the valve setting. The likelihood of a tank notbeing refilled is eliminated' SUMMARY OF THE INVENTION This objective isachieved by providing a reserve mechanism including a valve disposed inthe flow path between a tank containing air or other breathable gas andother components of the breathing apparatus. The valve includes twocooperating members, a valve seat member and a piston member, which arespring biased into a closed or flow impeding position. When the tankpressure exceeds the spring bias force, air from the tank presses openone of the valve members and flows to the other breathing apparatuscomponents. The valve may be opened manually to permit the unimpededflow of reserve air from the tank to the user when the tank pressuredrops below the preset level established by the spring bias force. Torefill the tank, gas from a compressor or other high pressure source isconnected to the tank via the valve. The pressure of gas from thissource opens the other valve member, permitting the tank to be refilledeven though the valve is not set to the open. reserve" position.

BRIEF DESCRIPTION OF THE DRAWINGS A detailed description of theinvention will be made with reference to the accompanying drawings,wherein like numerals designate corresponding parts in the severalfigures, The drawings are to scale.

FIG. I is a pictorial view showing utilization of the inventive reservevalve meehanisn in conjunction with a self-contained underwaterbreathing apparatus.

FIG. 2 is a transverse sectional view of the inventive reserve valvemechanism as seen generally along the line 22 of FIG. I. The valve isshown in the reserve position permitting unimpeded flow of reserve airfrom the scuba tank.

FIG. 3 is a transverse sectional view, as seen generally along the line3 3 of FIG. 2, and showing the cam shaft groove configuration. 1

FIG. 4 is a transverse sectional view like FIG. 2, but illustrating howthe scuba tank can be refilled even though the reserve valve is set tothe normal, nonreserve position.

FIG. 5 is a partial transverse sectional view like FIG. 4, illustratingthe flow of air from the scuba tank with the reserve valve in the normalposition.

DESCRIPTION OF THE PREFERRED EMBODIMENT -As shown in FIG. 1, the reservevalve mechanism 10 is used in conjunction with a scuba tank 11containing air or other breathable gas. With the control handle 12 inthe normal or non-reserve position shown in FIGS. 1, 4 and 5, air fromthe tank 11 is supplied via a conventional scuba regulator first stage13 and a hose 14 to the demand valve on the divers mouthpiece 15.

The'pressure in the tank 11 ordinarily drops in response to theconsumption of breathable gas by the diver. When only a small amount ofair remains in the tank 11, the pressure will be insufficient to open avalve 16 in the reserve mechanism 10, resulting in an interruption ofair flow to the diver. The diver will recognize from this interruptionthat his supply is almost exhausted, and will rotate the control handle12 to the reserve positiontFIG. 2) which permits the remaining air inthe tank 11 to flow to the mouthpiece l5. Accordingly, the diver canbreathe this reserve air while ascending to the surface. A feature ofthe reserve valve mechanism 10 concems operation during refilling of thetank 11. Normally the tank 11 is filled by removing the regulator 13 andconnecting an air compressor 18 or other high pressure source ofbreathable gas to the tank 11 via a hose 19 and the reserve mechanism10. Unlike prior art units, the inventive reserve mechanism 10 permitsthe tank 11 to be refilled regardless of inlet passageway 23 facilitatesair flow between the tank 11 and the valve 16 which is situated within abore 24 communicating to an outlet 25. In the embodiment shown, theregulator 13 is connected to the reserve mechanism by a threadedcoupling 26 received in the outlet 25.

An annular shoulder 27 separates the bore 24 from the outlet and servesas a stop for a generally annular valve seat member 28 which is slidablewithin the bore 24. A valve stem 29 extends loosely through the opening30 in the valve seat member 28, and terminates at a valve head 31 havinga diameter greater than the opening 30. The valve head 31 closes againstthe valve seat 28a to block air fiow between the tank 11 and the outlet25. The valve seat member 28 is biased toward the shoulder 27 by aspring 32 situated in thebore 24 and surrounding the stem 29. Asdescribed below, the member 28 abuts against the shoulder 27 when air isbeing supplied from the tank 11 in either the normal or reservecondition. As shown in FIG. 4, the valve seat member 28 is forced awayfrom the shoulder 27 when the tank 11 is being refilled with the controlhandle 12 in the normal" position.

The position of the valve stem 29 is controlled by a cam shaft 34 and asliding cam follower 35 situated within the bore 24. The cam shaft 34 isrotated by the handle 12. The cam shaft interior end 34a includes a pairof diagonally aligned, relatively shallow grooves 36 and a pair ofdiagonally aligned, relatively deep grooves 37 which are perpendicularto the grooves 36. A pair of diagonally aligned cam lobes 38 projectfrom the rear of the cam follower 35 and seat in either the grooves 36or 37 depending on the position of. the camshaft 34. Rotation of the camfollower 35 is prevented by a flat block 39 cooperating with a flat camfollower surface 40. The valve stem 29 is threaded to a tensionadjusting nut 41 situated in a recess 42 within the cam follower 35. Thebias spring 32 presses the nut 41 against an adjusting screw 43contained in a central opening 44 in the cam follower 35 between theradially disposed cam lobes 38. With this arrangement, when the handle12 is turned to the normal position (FIG. 5), the cam lobes 38 seat inthe deep grooves 37. The spring 32 biases the valve seat member 28against the shoulder 27, and urges the valve head 31 toward a closedposition against the valve seat 28a. However, if considerable airremains in the tank 1 1, the air pressure exerted in the direction ofthe arrows 45 will be sufficient to displace the valve head 31 away fromthe seat 28a. There will be unimpeded air flow from the tank 1 1 via thereserve mechanism 10 to the regulator 13 and the mouthpiece 15.

As the air in the tank 11 is consumed, the pressure exerted against thevalve head 31 will decrease. Eventually the pressure will drop to alevel which will not overcome the force of the bias spring 32. When thisoccurs, the spring 32 will force the valve head 31 against the valveseat 28a, closing the valve 16 and interrupting the flow of air to'thediver. The diver will recognize from this interruption that only alimited amount of air remains in the tank 11. Typically, the springforce is adjusted using the nut 41 so that the valve 16 will close whenthe tank pressure drops to about 300 psi for regular diving. However,for repetitive dives, cave diving or other applications where anelongated reserve is advantageous, the adjustment may be made so thatthe valve 16 will close at say 600 psi.

When the diver senses the interrupted flow indicating that the reservelevel has been reached, he rotates the control handle 12 to the reserveposition shown in FIG. 2. In this orientation, the cam lobes 38 seatwithin the shallow grooves 36, so that the cam follower 35 maintains thevalve head 31 away from the valve seat 28a; That is, the valve 16 isopened to permit the air remaining in the tank 11 to flow freely towardthe regulator 13 as indicated by the arrows 46.

To refill the tank 11, the regulator first stage 13 (FIG. 1) isdisconnected from the reserve mechanism 10, and the air compressor 18 isconnected via the hose 19 and a coupling 48 (FIGS. 1 and 4). If thecontrol handle 12 of the reserve mechanism 10 is in the reserve"position (FIG. 2), the valve 16 is open and air can flow freely from thecompressor 18 to the tank 11, in a direction opposite that indicated bythe arrows 46.

If the control handle 12 is in the normal position, the spring 32 willbias the valve 16 toward a closed position. However, as shown in FIG. 4,pressure of the air from the compressor 18 will act against the valveseat member 28, overcoming the counterforce exerted by the spring 32 andforcing the member 28 to slide away from the shoulder 27. The valve head31 will remain stationary, since it is restrained by the cam follower35. As a result, the valve 16 will open and the high pressure air willflow from the compressor 18 into the tank 11, as indicated by the arrows49. Thus the tank 11 can be filled regardless of whether the controlhandle 12 is in the normal or reserve position. The adjusting screw 43is used to insure that the valve head 31 abuts firmly against the valveseat 28a when the control handle 12 is in the normal position and theair pressure in the tank 11 is less than the force exerted by the spring32. The valve seat member 28 is provided with an O-ring 50 to preventescape of air from between that member and the bore 24. A pressurespring 51 and a tension nut 52 cooperate to compress a pair of packingdiscs 53, 54 between the housing 21 and the cam shaft 34 and controlhandle housing 12a respectively. This prevents the escape of air pastthecam shaft 34.

Intending to claim all novel, useful and unobvious features shown ordescribed, the inventor makes the following claims:

1. A reserve mechanism for use with a self contained breathingapparatus, said mechanism including a valve situated on the flow path toa tank supplying breathable gas to other components of said breathingapparatus, the improvement wherein said valve includes two cooperatingmembers situated in a closed, flowcommunicating interior chamber of saidmechanism, said members being biased to close against each other toblock the flow of gas through said chamber, said chamber having a firstport on one side of said valve and connectable to said tank and a secondport on the other side of said valve and connectable to said othercomponents or to a source of high pressure breathable gas, one of saidmembers opening in a first direction when the pressure of gas from saidtank, entrant said chamber via said first port, exceeds a preset levelto permit gas flow to other components of said breathing apparatus, theother of said members opening in the opposite direction when subjectedto the pressure of gas from said high pressure source, entrant saidchamber via said second port, to permit gas from said source to flow inthe reverse direction through said chamber to refill said tank eventhough said valve has not been unimpeded flow of reserve air from saidtank at less than said preset pressure.

2. A reserve valve mechanism for use with a selfeontained breathingapparatus having a tank for breathable gas, comprising:

a valve including a piston member having a valve head and'an annularvalve seat member, said piston member being movable with respect to saidvalve seat member only in a first direction, said valve seat memberbeing movable only in the opposite direction with respect to said pistonmember, relative motion'of either said piston or valve seat memberconditioning said valve between a closed position in which said valvehead abuts against said seat member to close the opening therethrough,and anopen position in which said valve head is spaced from said seatmember,

means biasing said piston member toward said closed position, and

means for connecting said tank to other components of said breathingapparatus or to a high pressure source of breathable gas via said valve,the pressure of breathable gas from said tank, when in excess of theforce of said biasing means, causing one of said valve members to move,opening said valve and permitting gas flow from said tank to said othercomponents, the pressure of gas from said source causing the other ofsaid valve members to move to open said valve and permit gas flowingfrom said source to refill said tank.

3. A reserve valve mechanism according to claim 2 shoulder to limitmovement of said valve seat member, said cam operated means beingdisposed within said housing and including a cam follower slideablydisposed in said interior bore.

5. A reserve valve mechanism according to claim 4 wherein said pistonmember includes a valve stem exa mounted within said bore, said borehaving an interior tending loosely through the opening in said valveseat member and operatively engaging 'said cam follower, said valve headbeing situated on the same side of said valve seat member as saidshoulder, said cam follower being situated on the opposite side of saidvalve seat member as said shoulder, said biasing means comprising aspring situated within said interior bore between said valve seat memberand said cam follower.

6. A reserve valve mechanism according to claim 5 wherein said camoperated means further includes a cam shaft within said interior boreand connected to a control handle extending exteriorly of said housing,said cam shaft cooperating with said cam follower to control theposition of said piston member in response to the orientation of saidcontrol handle.

7. A reserve valve mechanism according to claim 6 wherein said housingincludes an inlet passageway communicating to said interior bore betweensaid valve seat member and said cam follower and adapted for connectionto said tank, and an outlet communicating to said interior bore from theside of said valve seat member facing said valve head, said outlet beingadapted for connection either to said other components or to said sourceof breathable gas.

' 8. A scuba reserve mechanism facilitating the refilling of a scubabreathable gas supply tank regardless of whether the mechanism is in thereserve or normal position, comprising:

a housing having one port for connection to said supply tank and anotherport for connection either to a scuba regulator or to a refill source ofbreathable gas, there being a flow communicating path within saidhousing between said one and other ports,

a reserve valve situated in flow-blocking relationship in said flowcommunicating path, said reserve valve normally being biased to a closedposition, but being openable by the pressure of gas entrant through saidone port from said tank when said pressure is above a preselected valueto permit flow of such gas from said tank tosaid regulator, and

a valve component also situatedin flow-blocking relationship in saidpath, said valve component being biased to a closed position, said valvebeing openable by the pressure of gas entrant through said other portwhen said pressure exceeds a certain value to permit refilling of saidtank from said source even though said reserve valve remains biased tosaid closed position.

1. A reserve mechanism for use with a self contained breathingapparatus, said mechanism including a valve situated on the flow path toa tank supplying breathable gas to other components of said breathingapparatus, the improvement wherein said valve includes two cooperatingmembers situated in a closed, flowcommunicating interior chamber of saidmechanism, said members being biased to close against each other toblock the flow of gas through said chamber, said chamber having a firstport on one side of said valve and connectable to said tank and a secondport on the other side of said valve and connectable to said othercomponents or to a source of high pressure breathable gas, one of saidmembers opening in a first direction when the pressure of gas from saidtank, entrant said chamber via said first port, exceeds a preset levelto permit gas flow to other components of said breathing apparatus, theother of said members opening in the opposite direction when subjectedto the pressure of gas from said high pressure source, entrant saidchamber via said second port, to permit gas from said source to flow inthe reverse direction through said chamber to refill said tank eventhough said valve has not been opened manually, said mechanism alsohaving control means for manually opening said valve to permit theunimpeded flow of reserve air from said tank at less than said presetpressure.
 2. A reserve valve mechanism for use with a self-containedbreathing apparatus having a tank for breathable gas, comprising: avalve including a piston member having a valve head and an annular valveseat member, said piston member being movable with respect to said valveseat member only in a first direction, said valve seat member beingmovable only in the opposite direction with respect to said pistonmember, relative motion of either said piston or valve seat memberconditioning said valve between a closed position in which said valvehead abuts against said seat member to close the opening therethrough,and an open position in which said valve head is spaceD from said seatmember, means biasing said piston member toward said closed position,and means for connecting said tank to other components of said breathingapparatus or to a high pressure source of breathable gas via said valve,the pressure of breathable gas from said tank, when in excess of theforce of said biasing means, causing one of said valve members to move,opening said valve and permitting gas flow from said tank to said othercomponents, the pressure of gas from said source causing the other ofsaid valve members to move to open said valve and permit gas flowingfrom said source to refill said tank.
 3. A reserve valve mechanismaccording to claim 2 further comprising: cam operated means for manuallymoving said valve to said open position to permit unimpeded flow of gasfrom said tank to said other components when the pressure of gas fromsaid source is less than the force of said biasing means.
 4. A reservevalve mechanism according to claim 3 wherein said valve is contained ina housing having an interior bore, said valve seat member being slidablymounted within said bore, said bore having an interior shoulder to limitmovement of said valve seat member, said cam operated means beingdisposed within said housing and including a cam follower slideablydisposed in said interior bore.
 5. A reserve valve mechanism accordingto claim 4 wherein said piston member includes a valve stem extendingloosely through the opening in said valve seat member and operativelyengaging said cam follower, said valve head being situated on the sameside of said valve seat member as said shoulder, said cam follower beingsituated on the opposite side of said valve seat member as saidshoulder, said biasing means comprising a spring situated within saidinterior bore between said valve seat member and said cam follower.
 6. Areserve valve mechanism according to claim 5 wherein said cam operatedmeans further includes a cam shaft within said interior bore andconnected to a control handle extending exteriorly of said housing, saidcam shaft cooperating with said cam follower to control the position ofsaid piston member in response to the orientation of said controlhandle.
 7. A reserve valve mechanism according to claim 6 wherein saidhousing includes an inlet passageway communicating to said interior borebetween said valve seat member and said cam follower and adapted forconnection to said tank, and an outlet communicating to said interiorbore from the side of said valve seat member facing said valve head,said outlet being adapted for connection either to said other componentsor to said source of breathable gas.
 8. A scuba reserve mechanismfacilitating the refilling of a scuba breathable gas supply tankregardless of whether the mechanism is in the reserve or normalposition, comprising: a housing having one port for connection to saidsupply tank and another port for connection either to a scuba regulatoror to a refill source of breathable gas, there being a flowcommunicating path within said housing between said one and other ports,a reserve valve situated in flow-blocking relationship in said flowcommunicating path, said reserve valve normally being biased to a closedposition, but being openable by the pressure of gas entrant through saidone port from said tank when said pressure is above a preselected valueto permit flow of such gas from said tank to said regulator, and a valvecomponent also situated in flow-blocking relationship in said path, saidvalve component being biased to a closed position, said valve beingopenable by the pressure of gas entrant through said other port whensaid pressure exceeds a certain value to permit refilling of said tankfrom said source even though said reserve valve remains biased to saidclosed position.